Zootaxa: a New Species of Farlowella Eigenmann And

A new species of Farlowella Eigenmann and Eigenmann (Siluriformes: Loricariidae), a stickcatfish from Bolivia

MICHAEL E. RETZER Center for Biodiversity, Illinois Natural History Survey, Champaign, IL 61820, USA. E-mail: [email protected]

Abstract

Farlowella altocorpus is described from six specimens from a single locality on the Río Coroico, a tributary of the Río Beni in Bolivia. Farlowella altocorpus is a member of the Farlowella nattereri Steindachner species group and can be distinguished from other members of that group by a unique combination of characters: snout tip to mouth length 73–87% of pectoral fin length in adults, body depth 69–79% of pelvic fin length, body depth 49–53% of distance between pelvic and pectoral fins, head length 1.94–2.28 times length of snout tip to mouth, mid-ventral plates keeled, pectoral fins reach origins of pelvic fins, not having first anal and dorsal fin spines entirely darkly pigmented, anterior median lateral plates 14–16, posterior median lateral plates 16–18, post-anal plates 22–23, and abdominal plates 22–31.

Key words: Loricariidae, Farlowella, Río Coroico, Bolivia, new species

Introduction

Retzer and Page (1996) identified six species groups within the genus Farlowella E igenmann and Eigenmann. Within the Farlowella nattereri species group, they recognized five species: F. isbruckeri, F. hasemani, F. jauruensis, F. nattereri, and F. odontotumulus. The F. nattereri species group has a wide distribution in the Amazon River and upper Paraguay River basins and in the Essequibo River of Guyana. Recent collections from Bolivia revealed a new species of Farlowella. The new species has the unique combination of diagnostic characters (3 rows of abdominal dermal plates, 5 rows of trunk lateral dermal plates, diamond-shaped second row of lateral dermal plates, and short breeding odontodes forming patches on head and body) of the F. nattereri species group and is described herein and is contrasted with the other species of the F. nattereri species group.

Accepted by L. Page: 10 Jul 2006; published: 7 Aug. 2006 59 ZOOTAXA Materials and Methods 1282 Measurements (in mm) were made using dial or digital calipers. Counts and measurements follow Boeseman (1971), Retzer and Page (1996), and Schaefer (1997). Terminology of Schaefer (1997) with regards to lateral dermal plate patterns is followed although the method of counting anterior and posterior median plates follows Retzer and Page (1996). Statistical Package for Social Sciences (SPSS 11®) was used to explore mensural and meristic variation among the species of Farlowella. Analysis included descriptive statistics (means and ranges) of species and Principle Components Analysis (PCA). PCA of mensural data was based on Varimax rotation using the covariance matrix.

Measurements were log10 transformed. Results of PCA were used to determine which mensural characters were likely to provide diagnostic characters of the new species. PCA was based on individuals over 110 mm SL to avoid the influence of size on the analysis. The following comparative materials were used. Institutional abbreviations follow Leviton et al. (1985). Farlowella altocorpus: Bolivia—INHS 99773, 1 ex. holotype; INHS 36972, 2 ex. paratypes; SIUC 23150, 3 ex. paratypes Farlowella hasemani: Brazil—FMNH 55089, 1 ex.; FMNH 55090, 1 ex. Farlowella isbruckeri: Brazil—INHS 32943, 1 ex. paratype; MCP 36601, 2 ex.; MZUSP 27704, 1 ex. paratype; MZUSP 37641, 1 ex. holotype. Farlowella jauruensis: Brazil—FMNH 55088, 1 ex. holotype. Farlowella nattereri: Brazil—MCP 36599, 1 ex.; MCP 36600, 1 ex.; MZUSP 56116, 1 ex.; MZUSP 56217, 2 ex.; NMW 46497, 1 ex. holotype. Bolivia—AUM 23719, 8 ex.; CAS 77322, 2 ex. syntypes of Farlowella acestrichthys; INHS 36996, 3 ex.; FMNH 106987, 1 ex. Peru—INHS 36630, 3 ex.; INHS 54710, 1 ex.; SIUC 37127, 1 ex.; SIUC 28112, 2 ex.; UMMZ 66480, 1 ex. syntype of Farlowella acestrichthys. Farlowella odontotumulus: Brazil—MCP 36595, 5 ex. Ecuador—FMNH 99135, 1 ex. holotype. Venezuela—MCNG 25405, 1 ex. paratype.

Results

A PCA procedure revealed that the snout to mouth length, body depth at dorsal fin origin, body width at dorsal origin, orbit width, and fin-spine lengths accounted for a high proportion of variance among the species (Table 1).

Farlowella altocorpus, sp. nov (Figs. 1, 2)

Holotype. INHS 99773, 170.15 mm SL, sex unknown. Bolivia: La Paz State: Río Beni

60 © 2006 Magnolia Press RETZER Basin: Río Coroico, Caranavi, 4 August 1995, L.M. Page, B.M. Burr, M.H. Sabaj, J. ZOOTAXA Sarmiento & A.S. Barrera. 1282 Paratypes. INHS 36972, 2 ex., 87.82–91.69 mm SL; same data as holotype. – SIUC 23150, 3 ex., 69.59–138.89 mm SL same data as holotype.

TABLE 1. Component scores from PCA of the materials examined for individuals over 110 mm SL.

Component Character 1 2 3 4 Pre-dorsal length 0.074 -0.014 0.097 -0.048 Standard length 0.067 0.056 0.056 -0.178 Head length 0.166 -0.101 0.091 -0.032 Snout-to-eye length 0.236 -0.127 0.054 -0.084 Snout-to-mouth length 0.644 -0.355 -0.064 -0.346 Orbit width 0.029 -0.476 1.406 -0.093 Body depth -0.094 0.649 -0.376 -0.798 Dorsal fin length -0.016 -0.126 0.140 0.544 Pectoral fin length -0.067 0.004 -0.237 0.722 Pelvic fin length -0.150 -0.067 -0.095 1.035 Anal fin length -0.031 -0.136 -0.012 0.768 Snout-to-vent length 0.106 0.015 0.089 -0.204 Post-dorsal fin length 0.063 0.123 0.010 -0.323 Interorbital width -0.039 0.234 -0.052 -0.222 Pectoral fin origin to pelvic fin origin length -0.020 0.276 -0.147 -0.316 Body width -0.136 0.474 -0.359 -0.208 Eye to dorsal fin origin length -0.010 0.108 0.049 -0.122

Diagnosis: Farlowella altocorpus is a member of the F. nattereri group as defined by Retzer and Page (1996) and is distinguished from all non-members of this group except Farlowella gracilis Regan by having five rows of anterior lateral plates. The new species is distinguished from F. gracilis by having a snout-mouth length <50% of head length versus ≥ 50% in adults. Farlowella altocorpus is distinguished from other members of the F. nattereri group by possessing a unique combination of characters: snout tip to mouth length 73–87% of pectoral fin length in adults, body depth 69–79% of pelvic fin length, body depth 49–53% of distance between pelvic and pectoral fins, head length 1.94–2.28 times length of snout tip to mouth, mid-ventral plates keeled, pectoral fins reach origins of pelvic fins, not having first anal and dorsal fin spines entirely darkly pigmented, anterior median lateral plates 14–16, posterior median lateral plates 16–18, post-anal plates 22–23, and abdominal plates 22–31.

A NEW FARLOWELLA © 2006 Magnolia Press 61 ZOOTAXA Description: Largest specimen is the holotype, 170.15 mm SL. Morphometric data given 1282 in Table 2. Body of Farlowella altocorpus wide and deep relative to other Farlowella species. Snout short with tip slightly expands distally (Fig. 1). Head gently slopes forward from eye to base of snout; snout points upwards. Viewed dorsally, head roughly triangular with widest point at opercles and with weak preorbital ridge. Width of body posterior to dorsal fin noticeably less wide than anterior to dorsal fin. Visible portion of the cleithrum narrow and often in two parts. Pectoral fins long, reaching origin of pelvic fin. Pelvic fins extend beyond anus but do not reach origin of anal fin. Dorsal fin insertion slightly ahead of anal fin insertion. Three complete rows of abdominal plates.

TABLE 2. Standard length (SL) and measurements as percentage of SL in holotype and paratypes of Farlowella altocorpus.

Measurement Holotype Paratypes Range Mean ±SD Standard length (mm) 170.2 69.6–138.9 96.0±25.7 Pre-dorsal length 44.7 43.7–45.6 45.0±0.8 Head length 24.0 23.1–26.1 25.0±1.2 Snout-to-mouth length 11.3 10.2–13.2 11.7±1.2 Snout-to-eye length 19.7 19.0–22.0 20.7±1.2 Pectoral fin length 13.0 11.4–13.9 12.9±1.0 Pelvic fin length 8.7 6.9–9.4 8.1±0.9 Snout-to-vent length 39.7 40.0–41.6 41.0±0.7 Post-dorsal fin length 55.3 53.6–56.7 55.0±1.2 Interorbital width 5.3 5.1–5.6 5.3±0.2 Pectoral fin origin to pelvic fin origin length 12.4 11.1–13.3 11.7±0.9 Body width 6.6 6.4–8.1 7.0±0.7 Body depth 7.8 5.4–6.5 6.0±0.4 Eye to dorsal fin origin length 23.1 21.7–25.0 22.7±1.3

Number of teeth of upper left jaw 25–38; in lower left jaw 18–33. Total median lateral plates 32; pre-dorsal plates 8. Overall coloration of specimens in alcohol light to dark brown. Snout dark brown under and on sides and light dorsally. A dorso-lateral dark stripe runs along sides of body from head and fades in intensity posterior to dorsal fin. Posterior edges of plates within dark lateral stripe behind eye may lack pigmentation. Contrasting near-pigmentless dorsal stripe from snout to dorsal fin that fades posterior to dorsal fin. Near-pigmentless ventrally from mouth to anal fin but more pigmented posterior to anal fin. Small dark spots may occur on dorsal and ventral near-pigmentless stripes.

62 © 2006 Magnolia Press RETZER Small spots of brown melanophores on spines and rays of anal, dorsal, pectoral, and ZOOTAXA pelvic fins. Interradial membranes clear. Brown bands on upper and lower rays and 1282 membranes of caudal fin (Fig. 2); pigmentation of interradial membranes of caudal fin darker in smaller specimens and faint in larger specimens. Outer portion of upper lip pigmented with small discrete spots and inner portion unpigmented. Lower inner lip unpigmented and outer side with numerous faint melanophores.

FIGURE 1. Farlowella altocorpus, INHS 99773, holotype, 170.2 mm SL, dorsal, lateral, and ventral views. Photos by Michael Retzer.

FIGURE 2. Pigmentation of caudal fin of Farlowella altocorpus, SIUC 23150, 69.6 mm SL, lateral view. Photo by Michael Retzer.

Comparisons: Farlowella altocorpus is most similar to F. hasemani but differs in having a shorter snout-mouth length relative to the pectoral length in adults (73–87% in F. altocorpus, 91–110% in F. hasemani), and a shallower body depth relative to the pelvic fin length (69–79% in F. altocorpus, 86% in F. hasemani), fewer posterior median lateral plates (16–18 in F. altocorpus, 19-20 in F. hasemani), and pectoral fins reach origins of pelvic fins (vs. not reaching in F. hasemani). (Note that in Table 14 of Retzer and Page (1996), the snout-mouth length to pectoral length ratio for F. hasemani was incorrectly given as >1.0.) Farlowella altocorpus differs from F. nattereri in having a shorter and broader snout. This difference is reflected in a shorter snout-mouth length relative to the pectoral length in adults (73–87% in F. altocorpus, 91–138% in F. nattereri, Fig. 3), and not having first anal and dorsal fin spines entirely darkly pigmented. Note that in Table 14 of Retzer and Page (1996), the snout-mouth length to pectoral length ratio is incorrect due to a typographic error. The correct value in the table should have been >1.0 and was correctly given in the description for the species on page 57. The addition of new data herein has lowered the value from 1.0 to 0.91. The body depth of Farlowella altocorpus is not as deep as that of F. hasemani but is relatively deeper when compared to the other species of the F. nattereri species group. Farlowella altocorpus differs from F. isbruckeri in having a deeper body relative to pelvic fin length (69–79% in Farlowella altocorpus, 57–68% in F. isbruckeri), deeper body relative to pectoral fin length (45–51% in F. altocorpus, 37–41% in F. isbruckeri), and post-anal plates (22–23 in Farlowella altocorpus, 24 in F. isbruckeri). Farlowella altocorpus differs from F. juarensis in having a deeper body relative to pelvic fin length (69–79% in F. altocorpus, 64% in F. juaruensis) and a deeper body

64 © 2006 Magnolia Press RETZER relative to distance between pelvic and pectoral fin origins (49–53% in F. altocorpus, 47% ZOOTAXA in F. juaruensis). Farlowella altocorpus differs from F. juaruensis in having a shorter head 1282 length relative to snout tip to mouth length (1.94–2.28 times the length in F. altocorpus, 2.48 in F. juaruensis). Respectively, F. altocorpus differs from F. juaruensis in four meristic counts: anterior median lateral plates 14–16 versus 13, posterior median lateral plates 16–18 versus 14, post-anal plates 22–23 versus 24, and abdominal plates 22–31 versus 20.

FIGURE 3. Plot of snout-mouth length against interorbital width of Farlowella nattereri from Río Beni, Peru (AUM 23719), Farlowella altocorpus and syntypes of Farlowella acestrichthys, a synonym of Farlowella nattereri.

Farlowella altocorpus differs from F. odontotumulus in having a deeper body relative to pelvic fin length (69–79% in F. altocorpus, 60–64% in F. odontotumulus) and a deeper body relative to distance between pelvic and pectoral fin origins (49–53% in F. altocorpus, 39–46% in F. odontotumulus), and in having a longer head length relative to snout tip to mouth length (1.94–2.28 times the length in F. altocorpus, 1.67 in F. juaruensis). Mid-ventral lateral plate series of F. altocorpus is keeled; it is unkeeled in F. isbruckeri and F. odontotumulus.

Distribution: Farlowella altocorpus is currently known only from a single locality on the Río Coroico, (Río Beni Basin), La Paz State of Bolivia.

FIGURE 4. Farlowella acestrichthys, syntype, UMMZ 66480, 183.3 mm SL, photo by Michael Retzer.

FIGURE 5. Plot of PCA factor scores for six species of the Farlowella nattereri species group and the syntypes of Farlowella acestrichthys, synonym of Farlowella nattereri.

66 © 2006 Magnolia Press RETZER Etymology: From Latin, alto, meaning deep, and corpus, meaning body. The species ZOOTAXA epithet, altocorpus refers to its relatively high (alto) or deep body (corpus) relative to most 1282 of the other species of Farlowella. Comments: The upper Rio Beni is also the type locality of Farlowella acestrichthys Pearson. Retzer and Page (1996) considered F. acestrichthys to be a junior synonym of F. nattereri. Comparison of F. altocorpus to the F. acestrichthys syntypes indicates that the species are easily distinguished from each other. Farlowella altocorpus has a distinctly shorter and broader snout relative to F. acestrichthys (Figs. 1, 4). Retzer and Page (1996) also commented that F. nattereri is a complex of species. This observation is reflected in the plot of factor scores (Fig. 5). In Figure 5, the syntypes of F. acestrichthys are separate from specimens identified as F. nattereri (AUM 23719) that are also from the type locality of F. acestrichthys. As noted by Retzer and Page (1996), closer examination of populations of this wide-ranging species will be required to accurately access F. nattereri. One of the syntypes of F. acestrichthys (CAS 77322) does appear to group with F. altocorpus and F. hasemani; however, this is likely to be an artifact of the PCA because of the very large size of the specimen, 221.8 mm SL.

Acknowledgments

I would like to thank Jeff Stewart and Brooks Burr (Southern Illinois University at Carbondale), Roberto Reis (Pontificia Universidade Catolica do Rio Grande do Sul, Museu de Ciencias), Jon Armbruster (Auburn University), Don Taphorn (Museo de Ciencias Naturales), Mario de Pinna (Universidade de Sao Paulo), Mary Anne Rogers (Field Museum of Natural History), Doug Nelson (University of Michigan Museum of Zoology) and Tomio Iwamoto and David Catania (California Academy of Sciences) for the use of the specimens used in this description. Christopher Dietrich, Christopher Taylor and Kevin Cummings (Illinois Natural History Survey) provided photography equipment and expertise. Richard Vari (United States National Museum) provided expertise on etymology for the new species name. Mark Sabaj (Academy of Natural Sciences of Philadelphia), Christopher Taylor and Don Webb (INHS) offered helpful suggestions on the manuscript. The description was supported in part by the Planetary Biodiversity Inventory: All Catfish Species (Siluriformes), a project funded by the U.S. National Science Foundation (DEB-0415963).

References

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